1. Field of the Invention
The invention relates to a valve, more particularly to a foot-operated valve for faucets and the like.
2. Description of the Related Art
Presently, the control of water flow through most faucets installed in public places, such as in hospitals and public toilets, is usually accomplished by rotating a handle or by applying pressure on a lever. Thus, the risk of being infected with a disease is relatively high because of the need to operate the faucet by hand. In order to overcome this drawback, some establishments have installed faucets which incorporate a sensor to control water flow. However, such faucets can only provide a predetermined amount of water when in use and is incapable of satisfying the water needs of different people.
One of the applicants of the present invention has disclosed in co-pending U.S. patent application Ser. No. 08/199,885, filed on Feb. 22, 1994, a foot-operated valve which is convenient to use, which can minimize the risk of infection because it obviates the need for operating the same by hand, and which can be used to provide varying amounts of water to satisfy the needs of different people. The foot-operated valve comprises a valve housing, a valve stem, a spring means, a base, a push rod and a pedal. The valve housing is formed with a longitudinal bore which includes a front section and a rear section that has an internal diameter wider than that of the front section to form a shoulder which serves as a valve seat therebetween. The longitudinal bore has an open front end and a closed rear end. The valve housing is further formed with a water inlet hole that is communicated with the rear section of the longitudinal bore, and a water outlet hole that is communicated with the front section of the longitudinal bore. The valve stem extends into the longitudinal bore and is provided with a valve disc which is disposed in the rear section of the longitudinal bore. The valve stem has a front portion which extends sealingly through the open front end of the longitudinal bore. The spring means biases the valve disc to abut normally against the valve seat so as to block normally communication between the front and rear sections of the longitudinal bore. The base has the valve housing secured thereon and is provided with an upwardly extending mounting seat disposed adjacent to the valve housing. The base is formed with a cylindrical hole that is aligned with the valve stem. The push rod is received slidably in the cylindrical hole and has a head portion and a shank portion. The shank portion abuts against the front portion of the valve stem. The pedal has a rear end connected pivotally to the mounting seat and a bottom surface provided with a downwardly extending push plate that abuts against the head portion of the push rod. The pedal pivots when pressure is applied thereon, thereby causing the push plate to push the push rod further into the cylindrical hole so as to push the valve stem inwardly of the longitudinal bore to move the valve disc away from the valve seat against action of the spring means to permit water entering the rear section of the longitudinal bore via the water inlet hole to flow through the water outlet hole via the front section of the longitudinal bore.
Although the foot-operated valve can overcome the drawbacks of conventional water flow control devices commonly installed in faucets, there is still some room for improvement. For example, pressure must be applied on the pedal of the foot-operated valve continuously to obtain a continuous flow of water, thereby making the foot-operated valve somewhat inconvenient to use. Furthermore, the foot-operated valve is not adapted for use in a hot-and-cold water faucet system.